The present invention relates to a mobile communications terminal having a first loudspeaker for emitting sound signals in a normal mode of the communications terminal, a second loudspeaker for emitting sound signals in a hands-free mode of the communications terminal, an antenna and a signal processing device for processing signals which have been received by the antenna and for supplying processed signals to the first loudspeaker and to the second loudspeaker depending on whether the communications terminal is in the normal mode or in the hands-free mode, and further relates to a method for emitting sound signals from the communications terminal.
Mobile communications terminals of the abovementioned type can be used both in a normal mode, in which the communications terminal is held against a user's head, and for a hands-free mode, in which the user's head is arranged at a distance from the communications terminal. The first loudspeaker for a normal mode cannot, in principle, be used for a hands-free mode since it cannot produce the sound pressure levels which are required for a hands-free mode.
For this reason, an integrated second loudspeaker is provided for a hands-free mode, which in many cases is arranged on the opposite side of the communications terminal to the first loudspeaker, where sufficient space is available to accommodate the comparatively large second loudspeaker. The sound is normally emitted from the second loudspeaker either directly through outlet openings in the rear face of the communications terminal, in which case it is assumed that the first loudspeaker as well as a keypad and a display for the communications terminal are located on its front face.
Alternatively, it is also possible to pass the sound signals from the second loudspeaker, which is located within the housing of the communications terminal, via channels to openings in the housing surface.
The second loudspeaker, which, in the case of mobile communications terminals, is arranged on their rear face owing to the large amount of space required by hands-free loudspeakers, thus does not emit its sound energy in the direction of a user of a communications terminal. This leads to a dull hearing impression with low high-frequency levels, which can have a negative influence on the comprehensibility of speech. Because of this, the tonal quality difference between the hands-free mode and the normal mode in the case of present-day communications terminals is very great, and will increase further in future communications terminals which will have a wider speech signal bandwidth.
Against this background, the present invention is directed toward improving speech quality in the hands-free mode of mobile communications terminals, particularly those in which the hands-free loudspeaker is arranged on the rear face of the appliance, and also toward specifying a method for emitting sound signals from such a communications terminal.